Identify and implement top 5 code reduction

Identify top 5 opportunities to massively reduce the amount of code (lines of code) in any part of the repo: - Similar functionality that can be unified and reused - Code that has been valuable but no more - A front end component or a group of them duplicate another component/page functionality. Use the most modern and nice looking - etc. Now implement them :)

Top-5 code reductions shipped (net −1,438 lines, 56 files): retired the /welcome setup wizard for the docked checklist (+startOpen rule), single-homed roster reads, org_billing preamble, two get_or_404 folds, test fixtures. Quick gate + review lanes green; PR #6898 queued to the merge lane. Four larger cuts identified but gated (legacy respell layer, skynet tail, identity dual-write, contraction guard) — named in report. Visual check done: board + checklist render at 1440/400px. Memory: used mem-25697, mem-18424; 1 qa proposal refused.